Shell and tube-type of heat exchangers with baffles therein are commonly known in the art and of course are known and understood by those skilled in the art. An example of this type of heat exchanger is found in U.S. Pat. No. 1,904,875 wherein there is a shell with a liquid inlet and a liquid outlet and with baffles disposed therein for creating a serpentine flow path of the liquid through the shell and across the tubes disposed within the shell. In that instance, the baffle or baffles are arranged to have one edge spaced from the shell so that the liquid is permitted to flow through the space and thereby be directed across the tubes for optimum heat exchange.
Further, when liquid pressure is increased, or at some maximum amount, within the shell, then the prior art exchangers utilize spring-type liquid-pressure relief arrangements so that the liquid under excessive pressure will not flow into the interior of the shell and the arrangement thereby minimizes the liquid pressure flowing to the shell. An example of that type of external but spring-loaded relief means is shown in U.S. Pat. No. 4,642,149. However, in that example, it is necessary that the relief means be provided in an elaborate arrangement and external of the exchanger itself. As such, it requires external liquid connecting lines and it requires the relief valve or connector itself, and thus additional apparatus and provision for same are required.
The present invention improves upon the prior art by avoiding the need for external pressure relief apparatus, and thereby avoiding the need for the additional connectors, lines, and a special valve itself. Accordingly, the present invention provides for liquid-pressure relief means in the interior of the shell and arranged directly in connection with the baffle disposed within the shell. As such, the present invention provides for a simplified, improved, and inexpensive relief means which rapidly and accurately permits relief of the internal liquid pressure and which also efficiently re-establishes normal flow of the liquid around the spaced end of the baffle, as desired and when the liquid pressure is reduced from the excessive amount which activated the relief function.
The present invention thereby provides for an automatically adjusting relief mechanism which reacts in accordance with the liquid pressure within the shell and which provides for the simplified and accurate provision of a relief mechanism which is completely incorporated in the baffle itself. The relief mechanism of this invention thereby protects the parts of the exchanger itself and avoids damage to the exchanger which may otherwise be damaged by virtue of high-liquid pressure. As indicated, there is therefore no need for external connectors to achieve the liquid pressure relief, and therefore a more reliable and inexpensive, but yet accurate type of relief is provided since it is incorporated in the deflector baffle itself and since it is self-recovering and is not dependent upon any valve seat in order to re-establish itself in the desired deflective mode. That is, the externally arranged by-pass or relief valves commonly incorporate a valve seat which can be inadvertently retained in open position by means of a defective valve or seat or by debris within the liquid itself.